The present invention relates to vacuum nozzle assembly, in particular a vacuum nozzle assembly containing a valve assembly.
As disclosed in U.S. Pat. Nos. 5,228,916, 5,538,125 and 5,503,673, machines have been designed to coat pharmaceuticals with agents such as gelatin, to aid in the swallowing of the tablet. In coating the tablet it is desirable to coat the tablet with different colors which aid in identifying the product for both the pharmacist and the consumer. In order to coat both sides of a tablet with different colors it is common practice to invert the tablet from one side to the other in order to apply the different colors.
In commercial practice of coating the tablets, vacuum is used as a means of gripping the tablets as they are coated. Since the vacuum nozzles holding the tablets are just above the coating bath, if a tablet is missing or not properly placed in the holder, the coating solution will be pulled by vacuum into the nozzle. Once the coating solution is pulled by vacuum into the nozzle, the coating solution will solidify either plugging or significantly reducing the vacuum which makes it unlikely that the tablet can be held in place in the next cycle. Once the nozzle is plugged, the coating machine must be shut down and cleaned. Plugged nozzles is a significant cause of downtime and lost production.
One attempt at solving this problem is the use of photo electric eyes which check for missing tablets in the holders. If the electric eye detects a missing tablet the electric eye will shut down the machine so that an operator can manually replace the missing tablet in the machine. This semi-automatic approach is both labor intensive and inefficient.
It would be highly desirable that an automatic device be employed to prevent the vacuuming of coating solution into a tablet nozzle. Preferably the device would also allow the coating machine to remain in continuous operation if a tablet is missing and not require an operator to replace the tablet.